Instagram has added a new feature that lets you delete parts of static-image posts, which you can reuse as stickers in your own Stories and Reels.
This is within the three dots menu display from any publicly posted still image post. Upon activation, the system will recognize and focus on the subject entity you could then save as a different sticker.
You can then use that sticker in your stories and reels.
It is kind of similar to the cutout of image feature, which the parent company Meta also introduced lately for WhatsApp, and can unlock many new kinds of creative possibilities.

There are some limitations as well, that might stop this from coming into practice.
A vast majority of your feed would be probably video clips; thus, it might get hard to find static posts.

To create a sticker from a feed post, the creator also has to have posted publicly, while they need to have enabled permissions for other users to create cutouts from their content. Users can switch this off, and stop people from re-using their images, via their settings.

Also, if you make a cutout sticker from another person's post, and that user then removes their original, you'll also lose your sticker.

So there are some limitations to this process, but as noted, it could stimulate more creativity and open up new uses for visuals in the app.

The creative capacity is pretty wide-ranging, and it'll be interesting to see whether users really do start making their own custom stickers based off of posts in the app.

I mean, for instance, Pinterest's Shuffles app, which kind of allows its users to create collages a bit similarly, has really become something that's been an absolute smash with certain subgroups of users, particularly younger audiences, so this kind of treads along that track.

Perhaps that is a good sign. But anyway, that is yet another reason to consider posting on IG.